1. Field of the Invention
The present invention relates to an efficient and cost effective method for treating hydrocarbon-containing materials to remove solids, water, sulfur and/or other contaminants.
More particularly, the present invention relates to a method for cleaning hydrocarbon-containing materials including oil-containing materials such as well-fluids, drilling fluids, used oils, oil contaminated soils, or the like, under near critical, critical and/or supercritical conditions to produce a clean solid residue, an hydrocarbon residue and an aqueous residue, where the hydrocarbon residue is reusable, the solid residue is substantially free of hydrocarbons and aqueously extractable contaminants and the aqueous residue can be further cleaned to produce a purified water residue.
2. Description of the Related Art
Critical and supercritical extraction processes have been known for some time. Supercritical extraction has been used to clean oil and to desulfurize coal, but the technique has not been used to clean up drilling fluids so that the cutting are substantially free of hydrocarbon residue and/or aqueously soluble contaminants.
Thus, there is a need in the art for a method for cleaning drilling fluids and solid concentration derived therefrom generally via centrifugation to a purified solid material substantially free of hydrocarbon residues, drilling field chemicals and/or water soluble contaminants.